BRUSSELS, Feb 18 (Reuters) - European Union foreign policy chief Catherine Ashton voiced deep concern on Tuesday about escalating violence in Ukraine and called on the country's leadership to tackle the crisis.

"I am deeply worried about the grave new escalation in Kiev and the reported victims. I condemn all use of violence, including against public or party buildings," she said in a statement issued after a day of violent clashes between police and anti-government protesters in Ukraine.

"I urge the leadership of Ukraine to address the root causes of the crisis ... Political leaders must now assume their shared responsibility to rebuild trust and create the conditions for an effective solution to the political crisis," she said. (Reporting by Adrian Croft; editing by Barbara Lewis)